Abstract
The kinetics of elongation of individual internodes, the peduncle and panicle of
maize were studied in field experiments in Gatton (Australia) using two tropical cultivars,
and compared to similar data previously collected in Grignon (France) on a temperate
cultivar. Data for phytomer initiation and organ extension and appearance were related to
thermal time calculated from the temperature in the growing zone. Extension of internodes was
analysed using a four stage framework: - an initial exponential stage, transition to rapid
extension, rapid (linear) extension and transition to final length. The kinetics of internode
extension were similar in Gatton and Grignon, though the rates of processes differed.
Transition from stage 1 to stage 2 coincided with collar emergence. The commencement of rapid
extension of the peduncle coincided with a transient reduction in the rates of extension of
vegetative internodes. Further work is needed to assess whether they are effects of genotype
only, or genotype and environment.